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Dokládal L, Benková E, Honys D, Dupľáková N, Lee LY, Gelvin SB, Sýkorová E. An armadillo-domain protein participates in a telomerase interaction network. PLANT MOLECULAR BIOLOGY 2018; 97:407-420. [PMID: 29948659 DOI: 10.1007/s11103-018-0747-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 06/04/2018] [Indexed: 06/08/2023]
Abstract
Arabidopsis and human ARM protein interact with telomerase. Deregulated mRNA levels of DNA repair and ribosomal protein genes in an Arabidopsis arm mutant suggest non-telomeric ARM function. The human homolog ARMC6 interacts with hTRF2. Telomerase maintains telomeres and has proposed non-telomeric functions. We previously identified interaction of the C-terminal domain of Arabidopsis telomerase reverse transcriptase (AtTERT) with an armadillo/β-catenin-like repeat (ARM) containing protein. Here we explore protein-protein interactions of the ARM protein, AtTERT domains, POT1a, TRF-like family and SMH family proteins, and the chromatin remodeling protein CHR19 using bimolecular fluorescence complementation (BiFC), yeast two-hybrid (Y2H) analysis, and co-immunoprecipitation. The ARM protein interacts with both the N- and C-terminal domains of AtTERT in different cellular compartments. ARM interacts with CHR19 and TRF-like I family proteins that also bind AtTERT directly or through interaction with POT1a. The putative human ARM homolog co-precipitates telomerase activity and interacts with hTRF2 protein in vitro. Analysis of Arabidopsis arm mutants shows no obvious changes in telomere length or telomerase activity, suggesting that ARM is not essential for telomere maintenance. The observed interactions with telomerase and Myb-like domain proteins (TRF-like family I) may therefore reflect possible non-telomeric functions. Transcript levels of several DNA repair and ribosomal genes are affected in arm mutants, and ARM, likely in association with other proteins, suppressed expression of XRCC3 and RPSAA promoter constructs in luciferase reporter assays. In conclusion, ARM can participate in non-telomeric functions of telomerase, and can also perform its own telomerase-independent functions.
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Affiliation(s)
- Ladislav Dokládal
- Institute of Biophysics, The Czech Academy of Sciences, Královopolská 135, 61265, Brno, Czech Republic
- Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno, Czech Republic
- Department of Biology, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Eva Benková
- Institute of Science and Technology Austria, 3400, Klosterneuburg, Austria
| | - David Honys
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojova 263, 16502, Prague, Czech Republic
| | - Nikoleta Dupľáková
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojova 263, 16502, Prague, Czech Republic
| | - Lan-Ying Lee
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907-1392, USA
| | - Stanton B Gelvin
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907-1392, USA
| | - Eva Sýkorová
- Institute of Biophysics, The Czech Academy of Sciences, Královopolská 135, 61265, Brno, Czech Republic.
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Majerská J, Schrumpfová PP, Dokládal L, Schořová Š, Stejskal K, Obořil M, Honys D, Kozáková L, Polanská PS, Sýkorová E. Tandem affinity purification of AtTERT reveals putative interaction partners of plant telomerase in vivo. PROTOPLASMA 2017; 254:1547-1562. [PMID: 27853871 DOI: 10.1007/s00709-016-1042-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 11/04/2016] [Indexed: 05/15/2023]
Abstract
The life cycle of telomerase involves dynamic and complex interactions between proteins within multiple macromolecular networks. Elucidation of these associations is a key to understanding the regulation of telomerase under diverse physiological and pathological conditions from telomerase biogenesis, through telomere recruitment and elongation, to its non-canonical activities outside of telomeres. We used tandem affinity purification coupled to mass spectrometry to build an interactome of the telomerase catalytic subunit AtTERT, using Arabidopsis thaliana suspension cultures. We then examined interactions occurring at the AtTERT N-terminus, which is thought to fold into a discrete domain connected to the rest of the molecule via a flexible linker. Bioinformatic analyses revealed that interaction partners of AtTERT have a range of molecular functions, a subset of which is specific to the network around its N-terminus. A significant number of proteins co-purifying with the N-terminal constructs have been implicated in cell cycle and developmental processes, as would be expected of bona fide regulatory interactions and we have confirmed experimentally the direct nature of selected interactions. To examine AtTERT protein-protein interactions from another perspective, we also analysed AtTERT interdomain contacts to test potential dimerization of AtTERT. In total, our results provide an insight into the composition and architecture of the plant telomerase complex and this will aid in delineating molecular mechanisms of telomerase functions.
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Affiliation(s)
- Jana Majerská
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265, Brno, Czech Republic
- Central European Institute of Technology and Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137, Brno, Czech Republic
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Petra Procházková Schrumpfová
- Central European Institute of Technology and Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137, Brno, Czech Republic
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Ladislav Dokládal
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265, Brno, Czech Republic
| | - Šárka Schořová
- Central European Institute of Technology and Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137, Brno, Czech Republic
| | - Karel Stejskal
- Central European Institute of Technology and Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137, Brno, Czech Republic
| | - Michal Obořil
- Central European Institute of Technology and Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137, Brno, Czech Republic
| | - David Honys
- Institute of Experimental Biology, Academy of Sciences of the Czech Republic, v.v.i., Rozvojová 263, CZ-165 02, Prague, Czech Republic
| | - Lucie Kozáková
- Central European Institute of Technology and Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137, Brno, Czech Republic
| | - Pavla Sováková Polanská
- Central European Institute of Technology and Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137, Brno, Czech Republic
| | - Eva Sýkorová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, CZ-61265, Brno, Czech Republic.
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Gibalová A, Steinbachová L, Hafidh S, Bláhová V, Gadiou Z, Michailidis C, Műller K, Pleskot R, Dupľáková N, Honys D. Characterization of pollen-expressed bZIP protein interactions and the role of ATbZIP18 in the male gametophyte. PLANT REPRODUCTION 2017; 30:1-17. [PMID: 27896439 DOI: 10.1007/s00497-016-0295-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 11/15/2016] [Indexed: 05/21/2023]
Abstract
KEY MESSAGE : bZIP TF network in pollen. Transcriptional control of gene expression represents an important mechanism guiding organisms through developmental processes and providing plasticity towards environmental stimuli. Because of their sessile nature, plants require effective gene regulation for rapid response to variation in environmental and developmental conditions. Transcription factors (TFs) provide such control ensuring correct gene expression in spatial and temporal manner. Our work reports the interaction network of six bZIP TFs expressed in Arabidopsis thaliana pollen and highlights the potential functional role for AtbZIP18 in pollen. AtbZIP18 was shown to interact with three other pollen-expressed bZIP TFs-AtbZIP34, AtbZIP52, and AtbZIP61 in yeast two-hybrid assays. AtbZIP18 transcripts are highly expressed in pollen, and at the subcellular level, an AtbZIP18-GFP fusion protein was located in the nucleus and cytoplasm/ER. To address the role of AtbZIP18 in the male gametophyte, we performed phenotypic analysis of a T-DNA knockout allele, which showed slightly reduced transmission through the male gametophyte. Some of the phenotype defects in atbzip18 pollen, although observed at low penetrance, were similar to those seen at higher frequency in the T-DNA knockout of the interacting partner, AtbZIP34. To gain deeper insight into the regulatory role of AtbZIP18, we analysed atbzip18/- pollen microarray data. Our results point towards a potential repressive role for AtbZIP18 and its functional redundancy with AtbZIP34 in pollen.
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Affiliation(s)
- Antónia Gibalová
- Laboratory of Pollen Biology, Institute of Experimental Botany AS CR, v. v. i., Rozvojová 263, 165 02, Prague 6, Czech Republic
| | - Lenka Steinbachová
- Laboratory of Pollen Biology, Institute of Experimental Botany AS CR, v. v. i., Rozvojová 263, 165 02, Prague 6, Czech Republic
| | - Said Hafidh
- Laboratory of Pollen Biology, Institute of Experimental Botany AS CR, v. v. i., Rozvojová 263, 165 02, Prague 6, Czech Republic
| | - Veronika Bláhová
- Laboratory of Pollen Biology, Institute of Experimental Botany AS CR, v. v. i., Rozvojová 263, 165 02, Prague 6, Czech Republic
- Department of Physiology, Faculty of Science, Charles University in Prague, Viničná 7, 128 44, Prague 2, Czech Republic
- Institute of Physiology AS CR, v. v. i., Vídeňská 1083, 142 20, Prague 4, Czech Republic
- National Institute of Mental Health, Topolová 748, 250 67, Klecany, Czech Republic
| | - Zuzana Gadiou
- Laboratory of Pollen Biology, Institute of Experimental Botany AS CR, v. v. i., Rozvojová 263, 165 02, Prague 6, Czech Republic
| | - Christos Michailidis
- Laboratory of Pollen Biology, Institute of Experimental Botany AS CR, v. v. i., Rozvojová 263, 165 02, Prague 6, Czech Republic
| | - Karel Műller
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany AS CR, v. v. i., Rozvojová 263, 165 02, Prague 6, Czech Republic
| | - Roman Pleskot
- Laboratory of Cell Biology, Institute of Experimental Botany AS CR, v. v. i., Rozvojová 263, 165 02, Prague 6, Czech Republic
- Laboratory of Pavel Jungwirth, Institute of Organic Chemistry and Biochemistry AS CR, v. v. i., Flemingovo nám. 2, 166 10, Prague 6, Czech Republic
| | - Nikoleta Dupľáková
- Laboratory of Pollen Biology, Institute of Experimental Botany AS CR, v. v. i., Rozvojová 263, 165 02, Prague 6, Czech Republic
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany AS CR, v. v. i., Rozvojová 263, 165 02, Prague 6, Czech Republic.
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Hafidh S, Fíla J, Honys D. Male gametophyte development and function in angiosperms: a general concept. PLANT REPRODUCTION 2016; 29:31-51. [PMID: 26728623 DOI: 10.1007/s00497-015-0272-4] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 12/19/2015] [Indexed: 05/23/2023]
Abstract
Overview of pollen development. Male gametophyte development of angiosperms is a complex process that requires coordinated activity of different cell types and tissues of both gametophytic and sporophytic origin and the appropriate specific gene expression. Pollen ontogeny is also an excellent model for the dissection of cellular networks that control cell growth, polarity, cellular differentiation and cell signaling. This article describes two sequential phases of angiosperm pollen ontogenesis-developmental phase leading to the formation of mature pollen grains, and a functional or progamic phase, beginning with the impact of the grains on the stigma surface and ending at double fertilization. Here we present an overview of important cellular processes in pollen development and explosive pollen tube growth stressing the importance of reserves accumulation and mobilization and also the mutual activation of pollen tube and pistil tissues, pollen tube guidance and the communication between male and female gametophytes. We further describe the recent advances in regulatory mechanisms involved such as posttranscriptional regulation (including mass transcript storage) and posttranslational modifications to modulate protein function, intracellular metabolic signaling, ionic gradients such as Ca(2+) and H(+) ions, cell wall synthesis, protein secretion and intercellular signaling within the reproductive tissues.
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Affiliation(s)
- Said Hafidh
- Institute of Experimental Botany ASCR, v.v.i., Rozvojová 263, 165 00, Prague 6, Czech Republic
| | - Jan Fíla
- Institute of Experimental Botany ASCR, v.v.i., Rozvojová 263, 165 00, Prague 6, Czech Republic
| | - David Honys
- Institute of Experimental Botany ASCR, v.v.i., Rozvojová 263, 165 00, Prague 6, Czech Republic.
- Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, Viničná 5, 128 44, Prague 2, Czech Republic.
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5
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Reňák D, Gibalová A, Solcová K, Honys D. A new link between stress response and nucleolar function during pollen development in Arabidopsis mediated by AtREN1 protein. PLANT, CELL & ENVIRONMENT 2014; 37:670-83. [PMID: 23961845 DOI: 10.1111/pce.12186] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Heat shock transcription factors (Hsfs) are involved in multiple aspects of stress response and plant growth. However, their role during male gametophyte development is largely unknown, although the generative phase is the most sensitive and critical period in the plant life cycle. Based on a wide screen of T-DNA mutant lines, we identified the atren1 mutation (restricted to nucleolus1) in early male gametophytic gene At1g77570, which has the closest homology to HSFA5 gene, the member of a heat shock transcription factor (HSF) gene family. The mutation causes multiple defects in male gametophyte development in both structure and function. Because the mutation disrupts an early acting (AtREN1) gene, these pollen phenotype abnormalities appear from bicellular pollen stage to pollen maturation. Moreover, the consequent progamic phase is compromised as well as documented by pollen germination defects and limited transmission via male gametophyte. In addition, atren1/- plants are defective in heat stress (HS) response and produce notably higher proportion of aberrant pollen grains. AtREN1 protein is targeted specifically to the nucleolus that, together with the increased size of the nucleolus in atren1 pollen, suggests that it is likely to be involved in ribosomal RNA biogenesis or other nucleolar functions.
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Affiliation(s)
- David Reňák
- Laboratory of Pollen Biology, Institute of Experimental Botany v.v.i. ASCR, Rozvojová 263, Prague 6, 165 02, Czech Republic
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Oo MM, Bae HK, Nguyen TD, Moon S, Oh SA, Kim JH, Soh MS, Song JT, Jung KH, Park SK. Evaluation of rice promoters conferring pollen-specific expression in a heterologous system, Arabidopsis. PLANT REPRODUCTION 2014; 27:47-58. [PMID: 24550073 DOI: 10.1007/s00497-014-0239-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 02/10/2014] [Indexed: 06/03/2023]
Abstract
Promoters can direct gene expression specifically to targeted tissues or cells. Effective with both crop species and model plant systems, these tools can help researchers overcome the practical obstacles associated with transgenic protocols. Here, we identified promoters that allow one to target the manipulation of gene expression during pollen development. Utilizing published transcriptomic databases for rice, we investigated the promoter activity of selected genes in Arabidopsis. From various microarray datasets, including those for anthers and pollen grains at different developmental stages, we selected nine candidate genes that showed high levels of expression in the late stages of rice pollen development. We named these Oryza sativa late pollen-specific genes. Their promoter regions contained various cis-acting elements that could be responsible for anther-/pollen-specific expression. Promoter::GUS-GFP reporters were constructed and introduced into Arabidopsis plants. Histochemical GUS staining revealed that six of the nine rice promoters conferred strong GUS expression that was restricted to the anthers in Arabidopsis. Further analysis showed that although the GUS signals were not detected at the unicellular stage, they strengthened in the bicellular or tricellular stages, peaking at the mature pollen stage. This paralleled their transcriptomic profiles in rice. Based on our results, we proposed that these six rice promoters, which are active in the late stages of pollen formation in the dicot Arabidopsis, can aid molecular breeders in generating new varieties of a monocot plant, rice.
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Affiliation(s)
- Moe Moe Oo
- School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Republic of Korea
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7
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Hehl R, Bülow L. AthaMap web tools for the analysis of transcriptional and posttranscriptional regulation of gene expression in Arabidopsis thaliana. Methods Mol Biol 2014; 1158:139-56. [PMID: 24792049 DOI: 10.1007/978-1-4939-0700-7_9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The AthaMap database provides a map of verified and predicted transcription factor (TF) and small RNA-binding sites for the A. thaliana genome. The database can be used for bioinformatic predictions of putative regulatory sites. Several online web tools are available that address specific questions. Starting with the identification of transcription factor-binding sites (TFBS) in any gene of interest, colocalizing TFBS can be identified as well as common TFBS in a set of user-provided genes. Furthermore, genes can be identified that are potentially targeted by specific transcription factors or small inhibitory RNAs. This chapter provides detailed information on how each AthaMap web tool can be used online. Examples on how this database is used to address questions in circadian and diurnal regulation are given. Furthermore, complementary databases and databases that go beyond questions addressed with AthaMap are discussed.
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Affiliation(s)
- Reinhard Hehl
- Institut für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany,
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Borkotoky S, Saravanan V, Jaiswal A, Das B, Selvaraj S, Murali A, Lakshmi PTV. The Arabidopsis stress responsive gene database. INTERNATIONAL JOURNAL OF PLANT GENOMICS 2013; 2013:949564. [PMID: 23573074 PMCID: PMC3613098 DOI: 10.1155/2013/949564] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 02/12/2013] [Accepted: 02/18/2013] [Indexed: 05/23/2023]
Abstract
Plants in nature may face a wide range of favorable or unfavorable biotic and abiotic factors during their life cycle. Any of these factors may cause stress in plants; therefore, they have to be more adaptable to stressful environments and must acquire greater response to different stresses. The objective of this study is to retrieve and arrange data from the literature in a standardized electronic format for the development of information resources on potential stress responsive genes in Arabidopsis thaliana. This provides a powerful mean for manipulation, comparison, search, and retrieval of records describing the nature of various stress responsive genes in Arabidopsis thaliana. The database is based exclusively on published stress tolerance genes associated with plants.
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Affiliation(s)
- Subhomoi Borkotoky
- Centre for Bioinformatics, School of Life Science, Pondicherry University, R. V. Nagar, Kalapet, Puducherry 605014, India
| | - Vijayakumar Saravanan
- Centre for Bioinformatics, School of Life Science, Pondicherry University, R. V. Nagar, Kalapet, Puducherry 605014, India
| | - Amit Jaiswal
- Centre for Bioinformatics, School of Life Science, Pondicherry University, R. V. Nagar, Kalapet, Puducherry 605014, India
| | - Bipul Das
- Parasitology Division, Regional Medical Research Centre (RMRC-ICMR), Dibrugarh 786 001, India
| | - Suresh Selvaraj
- Department of Bioinformatics, SRM University, Tamil Nadu 603203, India
| | - Ayaluru Murali
- Centre for Bioinformatics, School of Life Science, Pondicherry University, R. V. Nagar, Kalapet, Puducherry 605014, India
| | - P. T. V. Lakshmi
- Centre for Bioinformatics, School of Life Science, Pondicherry University, R. V. Nagar, Kalapet, Puducherry 605014, India
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ER-localized auxin transporter PIN8 regulates auxin homeostasis and male gametophyte development in Arabidopsis. Nat Commun 2012; 3:941. [PMID: 22760640 DOI: 10.1038/ncomms1941] [Citation(s) in RCA: 204] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 05/31/2012] [Indexed: 02/02/2023] Open
Abstract
Auxin is a key coordinative signal required for many aspects of plant development and its levels are controlled by auxin metabolism and intercellular auxin transport. Here we find that a member of PIN auxin transporter family, PIN8 is expressed in male gametophyte of Arabidopsis thaliana and has a crucial role in pollen development and functionality. Ectopic expression in sporophytic tissues establishes a role of PIN8 in regulating auxin homoeostasis and metabolism. PIN8 co-localizes with PIN5 to the endoplasmic reticulum (ER) where it acts as an auxin transporter. Genetic analyses reveal an antagonistic action of PIN5 and PIN8 in the regulation of intracellular auxin homoeostasis and gametophyte as well as sporophyte development. Our results reveal a role of the auxin transport in male gametophyte development in which the distinct actions of ER-localized PIN transporters regulate cellular auxin homoeostasis and maintain the auxin levels optimal for pollen development and pollen tube growth.
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Reňák D, Dupl'áková N, Honys D. Wide-scale screening of T-DNA lines for transcription factor genes affecting male gametophyte development in Arabidopsis. ACTA ACUST UNITED AC 2011; 25:39-60. [PMID: 22101548 DOI: 10.1007/s00497-011-0178-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 11/06/2011] [Indexed: 12/29/2022]
Abstract
Male gametophyte development leading to the formation of a mature pollen grain is precisely controlled at various levels, including transcriptional, post-transcriptional and post-translational, during its whole progression. Transcriptomic studies exploiting genome-wide microarray technologies revealed the uniqueness of pollen transcriptome and the dynamics of early and late successive global gene expression programs. However, the knowledge of transcription regulation is still very limited. In this study, we focused on the identification of pollen-expressed transcription factor (TF) genes involved in the regulation of male gametophyte development. To achieve this, the reverse genetic approach was used. Seventy-four T-DNA insertion lines were screened, representing 49 genes of 21 TF families active in either early or late pollen development. In the screen, ten phenotype categories were distinguished, affecting various structural or functional aspects, including pollen abortion, presence of inclusions, variable pollen grain size, disrupted cell wall structure, cell cycle defects, and male germ unit organization. Thirteen lines were not confirmed to contain the T-DNA insertion. Among 61 confirmed lines, about half (29 lines) showed strong phenotypic changes (i.e., ≥ 25% aberrant pollen) including four lines that produced a remarkably high proportion (70-100%) of disturbed pollen. However, the remaining 32 lines exhibited mild defects or resembled wild-type appearance. There was no significant bias toward any phenotype category among early and late TF genes, nor, interestingly, within individual TF families. Presented results have a potential to serve as a basal information resource for future research on the importance of respective TFs in male gametophyte development.
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Affiliation(s)
- David Reňák
- Laboratory of Pollen Biology, Institute of Experimental Botany ASCR, Rozvojová 263, 165 02 Prague 6, Czech Republic
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Hehl R, Bülow L. Internet Resources for Gene Expression Analysis in Arabidopsis thaliana. Curr Genomics 2011; 9:375-80. [PMID: 19506727 PMCID: PMC2691667 DOI: 10.2174/138920208785699535] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 02/15/2008] [Accepted: 02/19/2008] [Indexed: 01/07/2023] Open
Abstract
The number of online databases and web-tools for gene expression analysis in Arabidopsis thaliana has increased tremendously during the last years. These resources permit the database-assisted identification of putative cis-regulatory DNA sequences, their binding proteins, and the determination of common cis-regulatory motifs in coregulated genes. DNA binding proteins may be predicted by the type of cis-regulatory motif. Further questions of combinatorial control based on the interaction of DNA binding proteins and the colocalization of cis-regulatory motifs can be addressed. The database-assisted spatial and temporal expression analysis of DNA binding proteins and their target genes may help to further refine experimental approaches. Signal transduction pathways upstream of regulated genes are not yet fully accessible in databases mainly because they need to be manually annotated. This review focuses on the use of the AthaMap and PathoPlant® databases for gene expression regulation analysis and discusses similar and complementary online databases and web-tools. Online databases are helpful for the development of working hypothesis and for designing subsequent experiments.
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Affiliation(s)
- Reinhard Hehl
- Technische Universität Braunschweig, Institut für Genetik, Spielmannstr. 7, D-38106 Braunschweig, Germany
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12
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Grant-Downton R, Le Trionnaire G, Schmid R, Rodriguez-Enriquez J, Hafidh S, Mehdi S, Twell D, Dickinson H. MicroRNA and tasiRNA diversity in mature pollen of Arabidopsis thaliana. BMC Genomics 2009; 10:643. [PMID: 20042113 PMCID: PMC2808329 DOI: 10.1186/1471-2164-10-643] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 12/30/2009] [Indexed: 11/10/2022] Open
Abstract
Background New generation sequencing technology has allowed investigation of the small RNA populations of flowering plants at great depth. However, little is known about small RNAs in their reproductive cells, especially in post-meiotic cells of the gametophyte generation. Pollen - the male gametophyte - is the specialised haploid structure that generates and delivers the sperm cells to the female gametes at fertilisation. Whether development and differentiation of the male gametophyte depends on the action of microRNAs and trans-acting siRNAs guiding changes in gene expression is largely unknown. Here we have used 454 sequencing to survey the various small RNA populations present in mature pollen of Arabidopsis thaliana. Results In this study we detected the presence of 33 different microRNA families in mature pollen and validated the expression levels of 17 selected miRNAs by Q-RT-PCR. The majority of the selected miRNAs showed pollen-enriched expression compared with leaves. Furthermore, we report for the first time the presence of trans-acting siRNAs in pollen. In addition to describing new patterns of expression for known small RNAs in each of these classes, we identified 7 putative novel microRNAs. One of these, ath-MIR2939, targets a pollen-specific F-box transcript and we demonstrate cleavage of its target mRNA in mature pollen. Conclusions Despite the apparent simplicity of the male gametophyte, comprising just two different cell types, pollen not only utilises many miRNAs and trans-acting siRNAs expressed in the somatic tissues but also expresses novel miRNAs.
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Gibalová A, Renák D, Matczuk K, Dupl'áková N, Cháb D, Twell D, Honys D. AtbZIP34 is required for Arabidopsis pollen wall patterning and the control of several metabolic pathways in developing pollen. PLANT MOLECULAR BIOLOGY 2009; 70:581-601. [PMID: 19449183 DOI: 10.1007/s11103-009-9493-y] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Accepted: 04/15/2009] [Indexed: 05/27/2023]
Abstract
Sexual plant reproduction depends on the production and differentiation of functional gametes by the haploid gametophyte generation. Currently, we have a limited understanding of the regulatory mechanisms that have evolved to specify the gametophytic developmental programs. To unravel such mechanisms, it is necessary to identify transcription factors (TF) that are part of such haploid regulatory networks. Here we focus on bZIP TFs that have critical roles in plants, animals and other kingdoms. We report the functional characterization of Arabidopsis thaliana AtbZIP34 that is expressed in both gametophytic and surrounding sporophytic tissues during flower development. T-DNA insertion mutants in AtbZIP34 show pollen morphological defects that result in reduced pollen germination efficiency and slower pollen tube growth both in vitro and in vivo. Light and fluorescence microscopy revealed misshapen and misplaced nuclei with large lipid inclusions in the cytoplasm of atbzip34 pollen. Scanning and transmission electron microscopy revealed defects in exine shape and micropatterning and a reduced endomembrane system. Several lines of evidence, including the AtbZIP34 expression pattern and the phenotypic defects observed, suggest a complex role in male reproductive development that involves a sporophytic role in exine patterning, and a sporophytic and/or gametophytic mode of action of AtbZIP34 in several metabolic pathways, namely regulation of lipid metabolism and/or cellular transport.
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Affiliation(s)
- Antónia Gibalová
- Laboratory of Pollen Biology, Institute of Experimental Botany ASCR, Rozvojová 263, Prague 6, Czech Republic
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Grant-Downton R, Hafidh S, Twell D, Dickinson HG. Small RNA pathways are present and functional in the angiosperm male gametophyte. MOLECULAR PLANT 2009; 2:500-12. [PMID: 19825633 DOI: 10.1093/mp/ssp003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Small non-coding RNAs are essential for development of the sporophyte, the somatic diploid phase of flowering plants. They are integral to key cellular processes such as defense, generation of chromatin structure, and regulation of native gene expression. Surprisingly, very little is known of their presence and function in the male haploid phase of plant development (male gametophyte/pollen grain), where dramatic cell fate changes leading to gametogenesis occur over just two mitotic divisions. We show that critical components of small RNA pathways are expressed throughout pollen development, but in a pattern that differs from the sporophyte. We also demonstrate that mature pollen accumulates a range of mature microRNAs, the class of small RNA most frequently involved in post-transcriptional regulation of endogenous gene expression. Significantly, these miRNAs cleave their target transcripts in developing pollen-a process that seemingly contributes to the purging of key regulatory transcripts from the mature pollen grain. Small RNAs are thus likely to make a hitherto unappreciated contribution to male gametophyte gene expression patterns, pollen development, and gametogenesis.
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15
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Borg M, Brownfield L, Twell D. Male gametophyte development: a molecular perspective. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:1465-78. [PMID: 19213812 DOI: 10.1093/jxb/ern355] [Citation(s) in RCA: 215] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Pollen grains represent the highly reduced haploid male gametophyte generation in flowering plants, consisting of just two or three cells when released from the anthers. Their role is to deliver twin sperm cells to the embryo sac to undergo fusion with the egg and central cell. This double fertilization event along with the functional specialization of the male gametophyte, are considered to be key innovations in the evolutionary success of flowering plants. This review encompasses important recent advances in our understanding of the molecular mechanisms controlling male gametophyte development. A brief overview of pollen development is presented, followed by a discussion of genome-wide transcriptomic studies of haploid gene expression. The progress achieved through genetic analysis of landmark events of male gametogenesis is discussed, with a focus on sperm cell production, and an emerging model of the regulatory network governing male germline development is presented. The review concludes with a perspective of the impact these data will have on future research strategies to further develop our understanding of the gametophytic control of pollen development.
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Affiliation(s)
- Michael Borg
- Department of Biology, University of Leicester, UK
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16
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Kim HJ, Oh SA, Brownfield L, Hong SH, Ryu H, Hwang I, Twell D, Nam HG. Control of plant germline proliferation by SCF(FBL17) degradation of cell cycle inhibitors. Nature 2008; 455:1134-7. [PMID: 18948957 DOI: 10.1038/nature07289] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Accepted: 07/24/2008] [Indexed: 01/23/2023]
Abstract
Flowering plants possess a unique reproductive strategy, involving double fertilization by twin sperm cells. Unlike animal germ lines, the male germ cell lineage in plants only forms after meiosis and involves asymmetric division of haploid microspores, to produce a large, non-germline vegetative cell and a germ cell that undergoes one further division to produce the twin sperm cells. Although this switch in cell cycle control is critical for sperm cell production and delivery, the underlying molecular mechanisms are unknown. Here we identify a novel F-box protein of Arabidopsis thaliana, designated FBL17 (F-box-like 17), that enables this switch by targeting the degradation of cyclin-dependent kinase A;1 inhibitors specifically in male germ cells. We show that FBL17 is transiently expressed in the male germ line after asymmetric division and forms an SKP1-Cullin1-F-box protein (SCF) E3 ubiquitin ligase complex (SCF(FBL17)) that targets the cyclin-dependent kinase inhibitors KRP6 and KRP7 for proteasome-dependent degradation. Accordingly, the loss of FBL17 function leads to the stabilization of KRP6 and inhibition of germ cell cycle progression. Our results identify SCF(FBL17) as an essential male germ cell proliferation complex that promotes twin sperm cell production and double fertilization in flowering plants.
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Affiliation(s)
- Hyo Jung Kim
- Division of Molecular Life Sciences, Pohang University of Science and Technology, Pohang 790-784, South Korea
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Oh SA, Bourdon V, Das 'Pal M, Dickinson H, Twell D. Arabidopsis kinesins HINKEL and TETRASPORE act redundantly to control cell plate expansion during cytokinesis in the male gametophyte. MOLECULAR PLANT 2008; 1:794-9. [PMID: 19825582 DOI: 10.1093/mp/ssn042] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Asymmetric cell division at pollen mitosis I (PMI) is required to specify the differential fate of the daughter vegetative and generative cells. Cytokinesis at PMI displays specialized features, and it has been suggested that there might be distinct molecular pathways underpinning different modes of cytokinesis in plants. Activation of the NACK-PQR MAP kinase signaling pathway, which is essential for somatic cell cytokinesis in tobacco, depends upon the NACK1 and NACK2 kinesin-related proteins. Their Arabidopsis orthologs, HINKEL (HIK) and TETRASPORE (TES), were reported to be essential for cytokinesis in somatic cells and in microsporocytes, respectively. More recently, HIK and TES were shown to have a functionally redundant role in female gametophytic cytokinesis. We report here that HIK and TES are co-expressed in microspores and developing pollen, and, through analysis of microspore and pollen development in double heterozygote mutants, the occurrence of cell plate expansion defects during cytokinesis at PMI. The data demonstrate a functionally redundant role for HIK and TES in cell plate expansion during male gametophytic cytokinesis, extending the concept that different modes of cytokinesis are executed by a common signaling pathway, but reinforcing the individuality of gametophytic cytokinesis in its requirement for either TES or HIK.
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Affiliation(s)
- Sung-Aeong Oh
- Department of Biology, University of Leicester, Leicester LE1 7RH, UK
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